diff --git a/Network/HTTP/ReverseProxy.hs b/Network/HTTP/ReverseProxy.hs
--- a/Network/HTTP/ReverseProxy.hs
+++ b/Network/HTTP/ReverseProxy.hs
@@ -268,12 +268,13 @@
                                        || (key == "connection" && value == "close"))
                $ WAI.requestHeaders req
   where
+    fromSocket = (("X-Real-IP", S8.pack $ showSockAddr $ WAI.remoteHost req):)
     addXRealIP =
         case wpsSetIpHeader wps of
-            SIHFromSocket -> (("X-Real-IP", S8.pack $ showSockAddr $ WAI.remoteHost req):)
+            SIHFromSocket -> fromSocket
             SIHFromHeader ->
                 case lookup "x-real-ip" (WAI.requestHeaders req) <|> lookup "X-Forwarded-For" (WAI.requestHeaders req) of
-                    Nothing -> id
+                    Nothing -> fromSocket
                     Just ip -> (("X-Real-IP", ip):)
             SIHNone -> id
 
diff --git a/http-reverse-proxy.cabal b/http-reverse-proxy.cabal
--- a/http-reverse-proxy.cabal
+++ b/http-reverse-proxy.cabal
@@ -1,5 +1,5 @@
 name:                http-reverse-proxy
-version:             0.4.0
+version:             0.4.0.1
 synopsis:            Reverse proxy HTTP requests, either over raw sockets or with WAI
 description:         Provides a simple means of reverse-proxying HTTP requests. The raw approach uses the same technique as leveraged by keter, whereas the WAI approach performs full request/response parsing via WAI and http-conduit.
 homepage:            https://github.com/fpco/http-reverse-proxy